Wednesday, November 11, 2020

Cerebro-oculo-facio-skeletal syndrome and ERCC5 mutation

Inspired by a patient

Le Van Quyen P, Calmels N, Bonnière M, Chartier S, Razavi F, Chelly J, El Chehadeh S, Baer S, Boutaud L, Bacrot S, Obringer C, Favre R, Attié-Bitach T, Laugel V, Antal MC. Prenatal diagnosis of cerebro-oculo-facio-skeletal syndrome: Report of three fetuses and review of the literature. Am J Med Genet A. 2020 May;182(5):1236-1242. doi: 10.1002/ajmg.a.61520. Epub 2020 Feb 13. PMID: 32052936.


Cerebro-oculo-facio-skeletal syndrome (COFS) is a rare autosomal recessive neurodegenerative disease belonging to the family of DNA repair disorders, characterized by microcephaly, congenital cataracts, facial dysmorphism and arthrogryposis. Here, we describe the detailed morphological and microscopic phenotype of three fetuses from two families harboring ERCC5/XPG likely pathogenic variants, and review the five previously reported fetal cases. In addition to the classical features of COFS, the fetuses display thymus hyperplasia, splenomegaly and increased hematopoiesis. Microencephaly is present in the three fetuses with delayed development of the gyri, but normal microscopic anatomy at the supratentorial level. Microscopic anomalies reminiscent of pontocerebellar hypoplasia are present at the infratentorial level. In conclusion, COFS syndrome should be considered in fetuses when intrauterine growth retardation is associated with microcephaly, arthrogryposis and ocular anomalies. Further studies are needed to better understand XPG functions during human development.

Ferri D, Orioli D, Botta E. Heterogeneity and overlaps in nucleotide excision repair disorders. Clin Genet. 2020 Jan;97(1):12-24. doi: 10.1111/cge.13545. Epub 2019 Apr 22. PMID: 30919937.


Nucleotide excision repair (NER) is an essential DNA repair pathway devoted to the removal of bulky lesions such as photoproducts induced by the ultraviolet (UV) component of solar radiation. Deficiencies in NER typically result in a group of heterogeneous distinct disorders ranging from the mild UV sensitive syndrome to the cancer-prone xeroderma pigmentosum and the neurodevelopmental/progeroid conditions trichothiodystrophy, Cockayne syndrome and cerebro-oculo-facio-skeletal-syndrome. A complicated genetic scenario underlines these disorders with the same gene linked to different clinical entities as well as different genes associated with the same disease. Overlap syndromes with combined hallmark features of different NER disorders can occur and sporadic presentations showing extra features of the hematological disorder Fanconi Anemia or neurological manifestations mimicking Hungtinton disease-like syndromes have been described. Here, we discuss the multiple functions of the five major pleiotropic NER genes (ERCC3/XPB, ERCC2/XPD, ERCC5/XPG, ERCC1 and ERCC4/XPF) and their relevance in phenotypic complexity. We provide an update of mutational spectra and examine genotype-phenotype relationships. Finally, the molecular defects that could explain the puzzling overlap syndromes are discussed.


No comments:

Post a Comment